OBJECTIVETo investigate the apoptosis of NK cells induced by the erythroleukemia cell line K562 in vitro.

METHODSPrimary NK cells isolated from the peripheral blood of healthy donors by magnetic-activated cell sorting were cultured with stem cell medium containing recombinant human interleukin-2 (rhIL-2). The NK cells and K562 cells were mixed and co-cultured at different E:T ratios for different time lengths. The apoptosis of NK cells and K562 cells were detected using PE-AnnexinV/7-AAD labeling and flow cytometry.

RESULTSThe purity of isolated NK cells reached (93.99∓4.22)%. At the same E: T ratio, the apoptotic rate of NK cells induced by K562 cells increased significantly with time. As the E:T ratio reduced, the apoptotic rate of the NK cells increased and their cytotoxic activity against K562 cells was attenuated.

CONCLUSIONK562 cells can induce the apoptosis of activated NK cells, which is one of the probable mechanisms of immune escape of tumors.

Apoptosis ; Cytotoxicity, Immunologic ; Humans ; K562 Cells ; Killer Cells, Natural ; cytology ; immunology ; Tumor Escape

Objective To explore the risk factors and potential mechanisms of hypertension events on the same day after transcatheter aortic valve implantation (TAVI) in patients with severe aortic stenosis. Methods Clinical data of patients who underwent TAVI for severe aortic stenosis at Department of Structural Heart Disease, Fuwai Hospital from December 2023 to February 2024 were retrospectively collected. According to the peak systolic blood pressure on the same day after surgery, patients were divided into a hypertension group (≥140 mm Hg) and a normal blood pressure group (<140 mm Hg). Logistic regression model was used to analyze the risk factors for hypertension on the same day after TAVI. Results A total of 54 patients after TAVI were included, with 41 patients in the hypertension group, including 18 males and 23 females, with an average age of (72.83±6.78) years; 13 patients in the normal blood pressure group, including 9 males and 4 females, with an average age of (70.00±7.57) years. Univariate analysis found that there were statistical differences in interventricular septal thickness [(13.71±1.98) mm vs. (12.23±1.59) mm, P=0.018], preoperative left ventricular ejection fraction (LVEF)>55% [33 (80.5%) vs. 6 (46.2%), P=0.040], and postoperative same-day LVEF>55% [33 (80.5%) vs. 4 (30.8%), P=0.003]. Multivariate logistic regression analysis found that postoperative same-day LVEF>55% [OR=10.173, 95%CI (1.044, 99.115), P=0.046] was an independent risk factor for hypertension on the same day after TAVI. Conclusion Myocardial contractility mainly participates in the occurrence of hypertension on the same day after TAVI. This study can not only improve our understanding of early hemodynamic changes after TAVI, but also provide a basis for the formulation of early hypertension treatment plans after TAVI to improve the short- and long-term prognosis of patients.